Cross Ref > OOP Basics

In VB.Net, the Object keyword is an alias for the base System.Object class and is the single base class all classes ultimately inherit from. Use the Inherits keyword to indicate the parent class and Inherits must precede all declarations in a class.

Syntax Example:   'Specify both namespace and class: Public Class Cyborg Inherits System.Object End Class 'Use Object alias for System.Objct: Public Class Cyborg Inherits Object End Class 'Default when not specified is System.Object: Public Class Cyborg End Class

In C#, the Object keyword is an alias for the base System.Object class and is the single base class all classes ultimately inherit from.

Syntax Example:   //Specify both namespace and class: public class Cyborg : System.Object { } //Use shortcut alias: public class Cyborg : Object { } //None, default is System.Object public class Cyborg { }

Declare and implement VB.Net classes after the form class or in their own .vb files. Unlike VB Classic, you can have more than one class in a .vb class file (VB classic uses .cls files for each class).

Public Class Cyborg

  Inherits Object

  Public Sub IntroduceYourself()

  MessageBox.Show("Hi, I do not have a name yet.")

 End Sub

End Class

Dim T1 As New Cyborg
T1.IntroduceYourself()

//No need to clean up with managed classes.

//The garbage collector will take care of it.

 VB.Net Class..Object (Class..End Class..New)

In C#, you use the class keyword to specify a class and you signify its parent with a colon and the name of the parent class. When you instantiate an object from a class, you use the new keyword.

public class Cyborg : System.Object
{
  public virtual void IntroduceYourself()
  {
    MessageBox.Show("Hi, I do not have a name yet.");  
  }
}

Cyborg T1 = new Cyborg();
T1.IntroduceYourself();

//No need to clean up with managed classes.

//The garbage collector will take care of it.

 C# Class..Object (class...new)  

VB.Net uses the Inherits keyword followed by the parent class name. If you do not include Inherits, your class inherits from System.Object.

Public Class Android

End Class

Public Class T-600

  Inherits Android

End Class

 VB.Net Inheritance (Inherits ParentClass)  

In C#, you use the class keyword followed by the parent class after a colon. If you leave out the parent class, your class inherits from System.Object.

public class Android

{

}

public class T-600 : Android

{

}

 C# Inheritance (: ParentClass)

In VB.Net you can set the visibility of a member field to any visibility: private, protected, public, friend or protected friend.

You can intialize a member field with a default when declared. If you set the member field value in your constructor, it will override the default value.

Finally, you can use the Shared modifier (no instance required) and ReadOnly modifier (similar to a constant).

Public Class Cyborg
  Private FSerialNumber As String = "A100"

  Public CyborgName As String
  Public CyborgAge As Integer
 

  Public Shared ReadOnly SeriesID As Integer = 100
End Class

 VB.Net Member Field

In C# you can set the visibility of a member field to any visibility: private, protected, public, internal or protected internal.

You can intialize a member field with a default when declared. If you set the member field value in your constructor, it will override the default value.

Finally, you can use the static modifier (no instance required) and readonly modifier (similar to a constant).

public class Cyborg : System.Object
{

  private string serialNumber = "A100";

  public string cyborgName; 
  public int cyborgAge = 0;
  public static readonly int seriesID = 100;
}

 C# Member Field  

VB.Net�uses the keywords sub and function. A sub does not return a value and a function does. Many programmers like to use the optional call keyword when calling a sub to indicate the call is to a procedure.

Public Class Cyborg

� Inherits Object

� Public Sub IntroduceYourself()

��� MessageBox.Show("Hi, I do not have a name yet.")

� End Sub

End Class

Dim T1 As New Cyborg
T1.IntroduceYourself()

In C#, you indicate a method with parens, no parens indicates a member property. Use the void return type for methods that do not return a value.

public class Cyborg : System.Object
{
  public virtual void IntroduceYourself()
  {
    MessageBox.Show("Hi, I do not have a name yet.");  
  }
}

Cyborg T1 = new Cyborg();
T1.IntroduceYourself();

 C# Member Method

The method modifiers include�MustOverride,�NotOverridable, Overridable, Overrides. Specify�VB.Net member modifiers as follows:

Public Overrides Function SomeFunction() As Double

The field modifiers include ReadOnly and Shared. Specify field modifiers as follows:

Public ReadOnly SomeField As String

The method modifiers are abstract, extern, new, partial, sealed, virtual, and override. Specify C# member modifiers as follows:

abstract SomeMethod() {..}

The field modifiers are const, readonly, static, volatile. Specify field modifiers as follows:

readonly int MyAge;

VB.Net uses a special property keyword along with special get and set methods to both get and set the values of properties. For a read-only property, leave out the set method. The value keyword is used to refer to the member field. Properties can make use of any of the access modifiers (private, protected, etc).

My preference for VB.Net code is to start member fields with "F" ("FName" in our example) and drop the "F" with properties that manage member fields ("Name" in our example).

Public Class Cyborg
  Private FCyborgName As String

  Public Property CyborgName()
    Get
      Return FCyborgName
    End Get

 
    Set(ByVal value)
      FCyborgName = value
    End Set
  End Property 

End Class

 VB.Net Member Property (property, get, set)

In C#, parens indicate a method and the lack of parens indicate a property. You use special get and set methods to both get and set the values of properties.

C# 3.0 introduced auto-implemented properties for use when no additional logic is required.

pulic int VendorID {get; set;}

For a read-only property, leave out the set method.

The value keyword is used to refer to the member field. Properties can make use of any of the access modifiers (private, protected, etc). It is common to use a lowercase member names for member fields ("name" in our example) and uppercase properties to manage member fields ("Name" in our example).

public class Cyborg : System.Object
{
  private string cyborgName;

 
  public string CyborgName
  {
    get {return cyborgName;}
    set {cyborgName = value;}
  }
}

 C# Member Property (no (), get, set)  

In VB.Net, you specify each class and each class member's visibility with an access modifier preceding class or member. The VB.Net access modifiers are the traditional Public, Protected, and Private plus the two additional .Net modifiers Friend and Protected Friend.

Friend indicates members are accessible from types in the same assembly. Protected Friend indicates members are accessible from types in the same assembly as well as descendant classes. OO purist might object to Friend and Protected Friend and I suggest you avoid them until you both fully understand them and have a need that is best suited by them.

Public Class Cyborg
  Inherits Object

  Private FName As String

End Class

 VB.Net Access Modifiers

In C#, you specify each class and each class member's visibility with an access modifier. The C# access modifiers are the traditional public, protected, and private plus the two additional .Net modifiers internal and protected internal.

Internal indicates members are accessible from types in the same assembly. Protected internal indicates members are accessible from types in the same assembly as well as descendant classes. OO purist might object to internal and protected internal and I suggest you choose private, protected, or public over them until you both fully understand them and have a need that is best suited by them.

public class Cyborg

{

private String FName;

}

 C# Access Modifiers